PNG or SVG, and when each one is the right answer

Picking the right file for a printed design. What transparency does, why a JPEG puts a white box on your shirt, and when vector wins.

Most printing problems arrive as file problems, and nearly all of them come down to two decisions: whether the background is transparent, and whether the artwork is made of pixels or of shapes.

Transparency is the one that ruins shirts

A JPEG cannot be transparent. Every JPEG has a background, and if the background looks white on your screen it will print as a white rectangle around your design. On a white shirt nobody notices. On a navy one it is a white box, and it is the single most common reason a print comes back looking wrong.

PNG can be transparent, which is why it is the safe default for anything that is not a photograph.

Pixels or shapes

• PNG is pixels. Fixed detail, fine for photographs and painted art, and it has a maximum useful size.
• SVG is shapes. It is drawn fresh at whatever size it is printed, so it is equally sharp on a pocket and on a blanket.

For a logo, lettering or a simple graphic, SVG is better in every way that matters. For a photograph, SVG is not an option and a large PNG is what you want.

A trap with transparent SVG

Holes in a shape have to be real holes. A doughnut drawn as a dark circle with a white circle on top looks correct on a white background and prints as a white disc in the middle on a coloured garment. In vector terms the hole must be part of the same path rather than a lighter shape covering it.

The same rule applies to anything you upload. If part of your design is meant to show the garment through it, that part must be transparent, not white.

Practical order of preference

1. SVG, for logos, type and flat graphics
2. PNG with a transparent background, for everything else
3. PNG with a background, only when you actually want the rectangle
4. JPEG, only for a photograph that fills its whole area